- 1/4 cup (60 mL) butter
- 3 cloves garlic, minced
- 1/4 cup (60 mL) all-purpose flour
- 1 tsp (5 mL) chopped fresh thyme
- 3/4 tsp (4 mL) salt
- 1/2 tsp (2 mL) pepper
- 2-1/2 cups (625 mL) milk
- 6 Yukon Gold potatoes, (about 2 lb/900 g)
- 1 small onion, sliced
- In saucepan, melt butter over medium heat; cook garlic, stirring, for 1 minute. Add flour, thyme, salt and pepper; cook, stirring, for 1 minute.
- Gradually whisk in milk; cook, whisking constantly, until boiling and thickened, about 8 minutes.
- Peel and thinly slice potatoes. Layer one-third in greased 8-inch (2 L) square baking dish or casserole dish; spread half of the onion over top. Repeat layers. Arrange remaining potatoes over top. Pour sauce over top, using back of knife to ease sauce between layers.
- Cover and bake in 350°F (180°C) oven for 1 hour. Uncover and bake until lightly browned and potatoes are tender, about 30 minutes. Let stand for 5 minutes before serving.